Bleaching of cellulose containing textile fiber material with a silicate-free stabilized peroxide bleaching bath

ABSTRACT

Cellulose fibers or mixtures thereof with synthetic fibers, especially with polyester fibers, are advantageously bleached by means of peroxide or agents capable of splitting off peroxide by adding to a peroxide containing silicate-free bleaching bath as stabilizer amino lower alkylene polyphosphonates and/or hydroxy alkane phosphonates together with hydroxy compounds or polyhydroxy compounds having 2 to 6 carbon atoms in their carbon chain and, if required, with polyamino carboxylic acids. The process according to the present invention has the advantage that deposit formation on the bleaching equipment as well as on the bleached goods is considerably reduced. The decrease in the average degree of polymerization which always takes place on bleaching is less when using the bleaching bath according to the present invention than when using silicate-containing bleaching baths and the degree of whiteness is at least as high as that achieved with silicate-containing bleaching baths while the ash values are considerably reduced, in contrast to those obtained with said silicate-containing baths. When using the combination of phosphonic acid with hydroxy compounds or polyhydroxy compounds, the amount of phosphonic acid can be considerably reduced.

ilnite tates Kling et a1.

[ Jan. 14, 11975 BLEACI-IING OF CELLULOSE CONTAINING TEXTILE FIBERMATERIAL WITH A SILICATE-FREE STABILIZED PEROXIDE BLEACl-IING BATH [75]lnventors: Alfred Kling, Ladcnburg; Viktor Specht, Dossenheim; Carmenliliofstetter, Mannheim-Kaefertal; Gundolf Eisenberg, Hemsbach, all ofGermany [73] Assignee: Benckiser-Knapsack GmbH,

Ladenburg Necker, Germany [22] Filed: Mar. 7, 1973 [21] Appl. No.:338,863

[30] Foreign Application Priority Data Mar. 10, 1972 Germany 2211578[52] U.S. C1 8/111, 162/76, 162/77, 162/78, 162/80, 252/186 [51] Int. ClD061 3/02 [58] Field of Search 162/78, 76, 80, 77; 423/272, 584;260/5024 P, 502.5; 252/186, 100; 8/111 [56] References Cited UNITEDSTATES PATENTS 2,927,082 3/1960 Young 8/111 X 3,234,140 2/1966 lrani252/186 3,388,069 6/1968 Lindner et a1. 252/186 X 3,645,666 2/1972Bailey et a1. 162/78 X 3,681,022 8/1972 Kibbel et a1. 423/584 X3,687,627 8/1972 Stalter .t 252/186 X Radimer et all. 260/5025 XKowalski 252/186 X [57] ABSTRACT Cellulose fibers or mixtures thereofwith synthetic fibers, especially with polyester fibers, areadvantageously bleached by means of peroxide or agents capable ofsplitting off peroxide by adding to a peroxide containing silicate-freebleaching bath as stabilizer amino lower alkylene polyphosphonatesand/or bydroxy alkane phosphonates together with hydroxy compounds orpolyhydroxy compounds having 2 to 6 carbon atoms in their carbon chainand, if required, with polyamino carboxylic acids. The process according to the present invention has the advantage that de posit formationon the bleaching equipment as well as on the bleached goods isconsiderably reduced. The decrease in the average degree ofpolymerization which always takes place on bleaching is less when usingthe bleaching bath according to the present invention than when usingsilicate-containing bleaching baths and the degree of whiteness is atleast as high as that achieved with silicate-containing bleaching bathswhile the ash values are considerably reduced, in contrast to thoseobtained with said silicate-containing baths. When using the combinationof phosphonic acid with hydroxy compounds or polyhydroxy compounds, theamount of phosphonic acid can be considerably reduced.

11 Claims, 2 Drawing Figures BLEACIIING OE CELLIJLOSE CONTAINING TEXTILEFIBER MATERIAL WITH A SILICATE-FREE STABILIZED PEROXIDE BLEACIIING BATHBACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention relates to a process of bleaching cellulose fibers and moreparticularly to an improved process of bleaching cellulose fibers ormixtures thereof with synthetic fibers, especially with polyesterfibers, by means of bleaching compositions containing phosphonic acids,to a bleaching composition useful in said process, and to the resultingbleached cellulose fibers or mixtures thereof with synthetic fibers.

2. Description of the Prior Art Cellulose fibers and especially cotton,linen, nettle, jute fibers are usually bleached by means of hydrogenperoxide or of compounds capable of splitting off of hydrogen peroxide.Bleaching is effected either in a long liquor with the goods to bebleached being placed, for instance, on reels or in a short liquorsimilar to the baths used in impregnating processes. Bleaching withhydrogen peroxide or the like can be carried out at a low temperature bythe so-called cold bleaching process in which the goods to be bleachedremain in the bleaching bath for a prolonged period of time. Shorteningof the bleaching time has been achieved by heating the goods to bebleached and impregnated with the bleaching bath in an I-box or similarapparatus to a temperature up to 100 C.

Recently, a procedure has been suggested according to which the goodsare bleached at a temperature between 100 C. and145 C. Bleachingaccording to this so-called high temperature process results in a veryconsiderable reduction of the bleaching time to between about 30 secondsand about 180 seconds.

While, when working in dilute bleaching baths, it has been recommendedto use silicate-free stabilizers (German Published Application No.1,021,823), it was not possible, heretofore, to omit addition ofsilicates to the impregnating bleaching bath, especially when proceedingaccording to the high temperature bleaching process. See, for instance,Meliand Textilberichte vol. 51, page 1,070 (1970) and the Germanprovisionally published Application No. 1,519,484. Thereby, silicatedeposits precipitated on the bleached goods and in the ap paratus couldnot be avoided and had to be accepted in the course of operation.

In order to remove such silicate deposits on the bleaching apparatus, itwas heretofore necessary to frequently interrupt the continuousbleaching procedure causing considerable economical disadvantages.Furthermore, the silicate precipitates have a highly disadvantageouseffect upon the bleached goods as this is well known.

SUMMARY OF THE INVENTION It is one object of the present invention toprovide a simple and effective process of bleaching cellulose fibers ormixtures thereof with synthetic fibers which process avoids thedisadvantages of the known bleaching processes.

Another object of the present invention is to provide a peroxidecontaining silicate-free bleaching composition for carrying out the newprocess of bleaching cellulose fibers and the like.

A further object of this invention is to provide cellulose fibers ortheir mixtures with synthetic fibers which have been bleached by theprocess according to the present invention.

In principle the process of the present invention which overcomes thedisadvantages of the known processes mentioned hereinabove, comprisesthe addition of, as stabilizer, amino lower alkylene polyphosphonatesand/or hydroxy lower alkane phosphonates together with aliphatic hydroxyor polyhydroxy compounds with 2 to 6 carbon atoms in their carbon chainand, if desired, with polyamino carboxylic acids to the bleaching bathwhich contains, as bleaching agent, hydrogen peroxide or agents capableof splitting off hydrogen peroxide in the usual concentration.

Suitable amino lower alkylene phosphonic acids are those which arederived from aliphatic or alicyclic hydrocarbons containing 1 to 6carbon atoms. Especially useful have proved to be amino di-(methylenephosphonic acid), amino tris-(methylene phosphonic acid), diethylenetriamino penta-(methylene phosphonic acid), 1,2 or 1,3-propylidenediamino tetra- (methylene phosphonic acid), ethylene diamino tetra-(methylene phosphonic acid), 1,2-cyclohexane diamino tetra-(methylenephosphonic acid), l-amino methyl cyclopcntylamino-(ZHetra-(methylenephosphonic acid).

Useful hydroxy alkane phosphonic acids are those which are dervied fromaliphatic or alicyclic hydrocarbons having 1 to 4 carbon atoms.Especially suitable have proved to be hydroxy ethane-1,1-diphosphonicacid and l-hydroxy propane-1,1,3 -triphosphonic acid.

Hydroxy compounds or, respectively, polyhydroxy compounds, such asgluconic acid, citric acid, erythritol, pentaerythritol, sorbitol, andtriethanolamine can be used advantageously.

Ethylene diamino tetra-acetic acid, diethylene triamino penta-aceticacid and nitrilo tri-acetic acid can be used as polyamino carboxylicacid additives.

tThe bleaching agent is preferably hydrogen peroxide in 30% to 35%solution. In place of hydrogen peroxide, there can also be used agentswhich are capable of splitting off oxygen. The amount of the stabilizeradded is preferably within the range of 2% to 30% and mostadvantageously between 6% and 15% calculated for 35% hydrogen peroxidesolution. Bleaching is carried out in an alkaline medium at a pH valuebetween about 9.0 and 12.0. As a result of such an alkaline reaction thephosphonic acids are present in the bleaching bath in the form of theircorresponding salts. Of course, it is also possible to add in place ofthe free acids their soluble salts and especially their alkali metalsalts.

An especially noteworthy advantage of the bleaching process according tothe present invention is to be seen in the fact that the decrease in theaverage degree of polymerization of the cellulose which always takesplace on bleaching is less pronounced than, and the degree of whitenessis as high as, when using silicatecontaining bleaching baths, but theash content of the bleached cellulose is considerably lower.

Wetting agents can be added to the bleaching bath in order to effectmore rapid wetting of the goods to be bleached. For this purpose allconventional wetting agents can be used which are effective in analkaline medium and which are compatible with the phosphonic acid andthe other components of the stabilizer addition. Suitable wetting agentsare those of the anionactive and non-ionogenic wetting agent type aswell as mixtures thereof. Preferred anion-active wetting agents are, forinstance, alkyl aryl sulfonates, fatty acid condensation products,protein degradation products, and others as well as their salts.Non-ionogenic compounds are, for instance, the compounds obtained byaddition of ethylene oxide to fatty alcohols, fatty acid amides, alkylphenols, and others.

The bleaching process according to the present invention can be carriedout at room temperature according to the cold bleaching process as wellas at a higher temperature and especially according to the socalled hightemperature process at temperatures ex ceeding 100 C. and preferablybetween 110 C. and 145 C. The proportion of phosphonic acid to the othercomponents of the stabilizer can vary in wide limits. Excellent resultsare achieved by using compositions in which the proportion of phosphonicacid to the hydroxy compounds or, respectively, to the polyhydroxycompounds is between 1:1 and :1. The combination according to thepresent invention permits to keep the amount of phosphonic acid in thestabilizer relatively low, thus improving the economy of the process.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following examples serve toillustrate the present invention without, however, limiting the samethereto.

Example 1 Pre-wetted crude cotton (squeezing effect: 60 is impregnatedwith the bleaching bath (squeezing effect: 100 in a conventional widebleaching equipment of the Artos type. The impregnated cotton fabric isheated to 95 C. in a steam shaft oven and is bleached at saidtemperature for 30 minutes. The following impregnating baths were usedfor bleaching:

a. heretofore used bleaching bath:

4.0 g./l. of a wetting agent consisting of a mixture of a phenylsulfonate with an ethoxylated fatty alcohol;

2.4 ml./l. of ethylene diamino tetra-acetic acid stabilizer;

24.0 ml./l. of waterglass solution 38 Be;

14.0 ml./l. of sodium hydroxide solution 50 Be;

35.0 ml./l. of 35% hydrogen peroxide solution.

b. Bleaching bath according to the present invention 4.0 g./l. of thesame wetting agent as given under 1 8.0 ml./l. of sodium hydroxidesolution 50 Be;

35.0 ml./l. of 35% hydrogen peroxide solution;

0.2 g./l. of diethylene triamino penta-(methylene phosphonic acid;

4.0 g./l. of gluconic acid;

0.4 g./l. of diethylene triamino penta-acetic acid.

Bleaching Results:

When carrying out the bleaching process with the composition of Example1a, the bleaching equipment shows a very high deposit of silicate andthe ash content of the bleached goods is relatively high.

In contrast thereto, no deposits were observed in the bleachingequipment, when bleaching with the composition lb according to thepresent invention. The degree of whiteness was not essentially differentfrom that on bleaching with the heretofore used composition 1a, but theash content of the goods was reduced by about 50 Example 2 Bucked cottonfabric was impregnated with the bleaching bath according to the presentinvention and was then heated in a pilot plant high temperature steamingequipment (Type Hoechst System Kleincwefers) at 140 C. for 60 seconds.The bleached cotton fabric was subsequently washed with hot water andfinally with cold water.

Composition of the bleachingbath:

1.5 g./l. of sodium hydroxide,

2.0 g./l. of the same wetting agent as used in Example 35.0 ml./l. of35% hydrogen peroxide solution,

0.6g./1. of diethylene triamino penta-(methylene phosphonic acid),

5.4 g./l. of sorbitol,

1.2 g./l. of diethylene triamino penta-acetic acid.

Bleaching Results:

Degree of Degree of whiteness polymerization Bucked cotton fabric 60.71980 Bleached cotton fabric 86.4 1600 Example 3 Cotton fabric wasbleached at C. in an AI-IIBA- type laboratory equipment with aproportion of fabric to bath of 1:40 for 1 hour. The active oxygencontent of the bleaching bath was determined in samples taken from thebath by titration according to the iodidethiosulfate method. Tap waterof 17 German hardness was used for preparing the bleaching bath. In asecond test 4 mg./l. of ferric ions were added. Bleaching was effectedwith the following bleaching bath:

Bleaching bath 3a:

4.0 ml./l. of sodium hydroxide solution 38 Be,

5.0 ml./l. of 30% hydrogen peroxide solution,

0.2 g./l. of ethylene diamino tetra-acetic acid,

0.7 g./l. of sodium tripolyphosphate.

Bleaching bath 3b (according to the present invention:

4.0 ml./l. of sodium hydroxide solution 38 Be,

5.0 ml./l. of 30% hydrogen peroxide solution,

0.2 g./l. of ethylene diamino tetra-(methylene phosphonic acid),

0.2 g./l. of gluconic acid.

The attached graphs of FIGS. 1 and 2 illustrate the results achievedwith the above-indicated bleaching baths. In these graphs there isplotted the amount of activated oxygen in mg. per 100 ml. of bleachingbath (ordinate), while the symbols given on the abscissa represent thefollowing data:

T,, at the beginning of the bleaching process,

T, at 40 C.,

T at 85 C.,

T at 85 C. after 20 minutes,

T, at 85 C. after 40 minutes,

T at 85 C. after 60 minutes.

It is evident from the curves of FIG. 1 illustrating the activatedoxygen content in the bleaching bath, that the oxygen content veryrapidly decreases as soon as a temperature of 85 C. is attained. Thesolid line indicates the values obtained without the addition of ferricions while the dotted line illustrates the results achieved when addingferric ions to the bleaching bath. It follows that the oxygendecomposition is even more pronounced in the presence of ferric ions. Inboth tests with or without ferric ions, i.e., when using a bleachingbath according to the prior art, insufficient stabilization wasachieved. As a result thereof, the degree of whiteness was only 78.1 or,respectively, 73.2 (in the presence of ferric ions). The degree ofwhiteness was determined with the Filter R 46 by means of the Elepho device.

The Elrepho apparatus with filter R 46 used for determining the degreeof whiteness is an electric remission photometer of the firm Carl Zeisswith a band elimination filter having its optimum transmission at 460nm.

In contrast to these results the activated oxygen content of thebleaching bath 3b according to the present invention as shown by thesolid line curve of FIG. 2 was diminished only to an extentcorresponding to the actual consumption of oxygen due to the bleachingeffect. In the presence of ferric ions as indicated by the dotted linecurve of FIG. 2, the decrease in activated oxygen was slightly greaterbut still within such limits as they correspond to an ideal bleachingprocedure. This is clearly demonstrated by the degree of whiteness of80.0 or, respectively, 81.5 in the presence of ferric ions.

Example 4 15.0 g. of desized cotton fabric were bleached with thecompositions given hereinafter in a laboratory equipment of theMulticolor" type of the firm Pretema A.G. whereby the proportion offabric to bleaching bath was 1:30, after heating the fabric in said bathto a temperature of 125 C. within 30 minutes and then continuing heatingat said temperature for 30 more minutes. The water used for preparingthe bleaching bath corresponds to a magnesium hardness of 5 Germanhardness. The residual oxygen content of the baths was determined afterthe test was completed.

Composition 4A:

5.0 ml./l. of 30% hydrogen peroxide,

x ml./l. of sodium hydroxide solution sufficient to adjust the bleachingbath to a pH of 12.0,

0.14 g./l. of diethylene triamino penta-(methylene phosphonic acid),

0.08 g./l. of diethylene triamino penta-acetic acid,

0.22 g./l. of gluconic acid.

Degree of Degree Ash Rcsidunl polymcriof cnnoxygen zntion whiteness tentStarting fabric 1840 58.6 1.0 Composition 4;: 1760 76.0 0.27 73 "/rComposition 4b [720 80.5 0.60 58.5

In another test bleaching was effected as described hereinabove with thefollowing compositions and with the addition of 4 mg./l. of ferric ionsto each bleaching bath.

Composition 4 c:

5 ml./l. of 30% hydrogen peroxide solution x ml./l. of sodium hydroxidesolution sufficient to adjust the pH-value of the bleaching bath to a pHof 1.0 g./l. of l-hydroxy propane-1,1,3-triphosphonic acid.

Composition 4 d:

5.0 ml./l. of 30% hydrogen peroxide solution,

x ml./l. of sodium hydroxide solution sufficient to adjust the pH-valueof the bleaching bath to a pH of 6.67 ml./l. of waterglass solution 30Be.

Bleaching Results:

The above given data clearly show that, when using the silicate-freestabilizers according to the present invention low ash contents and asatisfactory degree of polymerization are achieved on working under hightemperature condition, whereby the degree of whiteness is about the sameas that achieved on bleaching with the addition of silicate.Furthermore, these tests demonstrate that, when using the phosphonicacid alone, a considerably higher amount thereof must be used than whenusing its combination with hydroxy compounds or, respectively,polyhydroxy compounds.

In place of the amino alkylene phosphonic acids used in the precedingexamples, there may be employed corresponding amounts of other aminoalkylene phosphonic acids and/or hydroxy alkane phosphonic acids. Ingeneral, suitable amino alkylene phosphonic acids correspond to thefollowing Formula I R OH \ CH P'O I wherein x indicates the numerals 2and 3; y indicates the numerals to 4; while R and R both are the groupof the Formula on CH2 P 0 one of R and R is the group of the Formula andthe other one is hydrogen or both R and R indicate hydrogen; or C. Rindicates the group of the Formula OH CH P -O or d. the group of theFormula olt (III, e J='-O Oll (CI-I, s (ca, w n

2 m a n CII l:=-O

2 Oll in which m and n are one of the numerals l to 3. In general,suitable hydroxy alkane diphosphonic acids correspond to the followingFormula II:

0 R 0 n l n a0 P c P on I l I OH R8 OH in which R is hydrogen, hydroxyl,the amino group, a lower alkylamino group, a di-lower alkyl amino group,or lower alkyl with l to 8 carbon atoms, and

R is hydrogen or lower alkyl with I to 10 carbon atoms.

In place of the amino alkylene phosphonic acids and hydroxyalkanediphosphonic acids mentioned hereinabove and used in the Examples, therecan be employed the following acids, although the present invention isnot limited thereto:

Dipropylene triamino penta-(methylene phosphonic acid),1,3-diamino-2-propanol tetra-(methylene phosphonic acid),

1,2-bis-(amino methyl) cyclobutane (methylene phosphonic acid),

amino tris-(ethylidene phosphonic acid),

amino tris-(isopropylidene phosphonic acid),

tetra- OH diamino diethyl sulfido tetra-(methylene phosphonic CH P= 0and I 2 l-amino ethane-l,l-d1phosphon1c acid,

OH l-hydroxy ethane-1,l,2-triphosphonic acid,

1,3-diamino-2-propanol tetra-(methylene phos- R indicates the group ofthe Formula phonic acid),

OH CH P\ O OH (c11 52H gm (on N wherein R indicates hydrogen or hydroxyland R indicates hydrogen or alkyl, especially lower alkyl, such asmethyl or ethyl; or

R and R together with the two carbon atoms to which they are attached,form a cycloalkyl ring, preferably with four to six carbon atoms such ascyclobutyl, cyclopentyl, or cyclohexyl, while 0 and 2 indicate one ofthe numerals 0 and l, and R indicates hydrogen or the group of theFormula and others. Mixtures of such phosphonic acids can, of course,also be used.

In place of the hydroxy compounds or, respectively, polyhydroxycompounds mentioned hereinabove and used in the Examples, there can alsobe employed tartaric acid, malic acid, glucuronic acid, and others.

In place of the polyamino carboxylic acid additives mentionedhereinabove and used in the Examples, there can be employed N-hydroxyethyl ethylene diamino tri-acetic acid, N,N-(Z-hydroxy ethyl) glycine,1,3-

diamino-Z-propanol tetra-acetic acid, and others.

As stated hereinabove, the preferred bleaching agent is hydrogenperoxide which is used, depending upon the proportion of goods to bebleached to bleaching bath, in a concentration in the bleaching bathbetween about 1 g./l. and about 35 g./l. and preferably between about 3g./l. and about 15 g./l. calculated for 100 hydrogen peroxide. In placeof hydrogen peroxide, there can also be employed alkali metal peroxidessuch as sodium peroxide, alkali metal perborates, percarbonates, orperphosphates. The preferred bleaching agent, how ever, is hydrogenperoxide.

It has been pointed out hereinabove in Example 1, that when adding waterglass to the bleaching bath, the bleaching equipment must be cleaned andbleaching must be interrupted every 8 to 14 days in order to removesilicate deposits on the bleaching equipment. Usually this interruptionlasts for 3 to 8 hours. In contrast thereto, when bleaching with ableaching bath according to the present invention, no such repeated andtime consuming cleaning of the equipment is required.

It may also be mentioned that when bleaching with a hydrogen peroxidebath but without the addition of the stabilizing agent according to thepresent invention, the degree of polymerization is reduced, forinstance, when proceeding according to Example 2, to a value of about1,000, i.e., to only about 50 of the initial degree of polymerization ofthe fabric to be bleached.

The ferric ions are added, for instance, in Examples 3 and 4 in the formof ferric chloride.

Of course, many changes and variations in the bleaching procedure andthe bleaching bath composition and the like may be made by those skilledin the art in accordance with the principles set forth hereinabove andin the claims annexed hereto.

We claim:

1. In a process of bleaching cellulose containing textile fiber materialwith a peroxide containing bleaching bath, the improvement whichconsists in 1. providing a peroxide-containing bleaching bath free ofsilicate and adjusted to a pH between about 9.0 and about 12.0; 2.adding to said bath a stabilizing agent consisting of a mixture of a. analiphatic hydroxy compound with 2 to 6 carbon atoms in its hydrocarbonchain, and b. a phosphonic acid compound selected from the groupconsisting of an amino alkylene phos phonic acid, a hydroxy alkanephosphonic acid, a water soluble salt of said phosphonic acids, andmixtures thereof, and

3. bleaching the cellulose-containing textile fiber material with saidstabilizing agent containing bath without substantially reducing thedegree of polymerization of the cellulose present in the fiber material.

2. The process of claim 1, in which the stabilizing agent is added tothe bleaching bath in an amount between about 2 and about 30 '70calculated for 35% hydrogen peroxide present therein.

3. The process of claim 1, in which the stabilizing agent is added tothe bleaching bath in an amount between about 6 and about 15 calculatedfor 35% hydrogen peroxide present therein.

4. The process of claim 1 further comprising adding to the silicate-freehydrogen peroxide-containing bleaching bath, in addition to thestabilizing agent, a polyamino carboxylic acid.

5. The process of claim 1, in which the alkylene group of thestabilizing amino alkylene phosphonic acid has 1 to 6 carbon atoms.

6. The process of claim 1, in which the alkane group of the stabilizinghydroxy alkane phosphonic acid has 1 to 3 carbon atoms.

7. The process of claim 1, in which the stabilizing hydroxy compound isa compound selected from the group consisting of gluconic acid, citricacid, erythritol, pentaerythritol, sorbitol, and triethanolamine.

8. The process of claim 4, in which the polyamino carboxylic acid is anacid selected from the group consisting of ethylene diamino tetra-aceticacid, nitrilo triacetic acid, and diethylene triamirno penta-aceticacid.

9. The process of claim 1, in which bleaching is effected at atemperature between about C. and about C.

10. The process of claim 1, in which the cellulosecontaining textilefiber material is a fiber material containing cellulose fibers inmixture with synthetic fibers.

11. The process of claim 1, in which the cellulose containing textilefiber material is a fiber material containing cellulose fibers inmixture with polyester fibers.

1. IN A PROCESS OF BLEACHING CELLULOSE CONTAINING TEXTILE FIBER MATERIALWITH A PEROXIDE CONTAINING BLEACHING BATH, THE IMPROVEMENT WHICHCONSISTS IN
 1. PROVIDING A PEROXIDE-CONTAINING BLEACHING BATH FREE OFSILICATE AND ADJUSTED TO A PH BETWEEN ABOUT 9.0 AND ABOUT 12.0; 2.ADDING TO SAID BATH A STABILIZING AGENT CONSISTING OF A MIXTURE OF A. ANALIPHATIC HYDROXY COMPOUND WITH 2 TO 6 CARBON ATOMS IN ITS HYDROCARBONCHAIN, AND B. PHOSPHONIC ACID COMPOUND SELECTED FROM THE GROUPCONSISTING OF AN AMINO ALKYLENE PHOSPHONIC ACID, A HYDROXY ALKANEPHOSPHONIC ACID, A WATER SOLUBLE SALT OF SAID PHOSPHONIC ACIDS, ANDMIXTURES THEREOF, AND
 2. adding to said bath a stabilizing agentconsisting of a mixture of a. an aliphatic hydroxy compound with 2 to 6carbon atoms in its hydrocarbon chain, and b. a phosphonic acid compoundselected from the group consisting of an amino alkylene phosphonic acid,a hydroxy alkane phosphonic acid, a water soluble salt of saidphosphonic acids, and mixtures thereof, and
 2. The process of claim 1,in which the stabilizing agent is added to the bleaching bath in anamount between about 2 % and about 30 % calculated for 35% hydrogenperoxide present therein.
 3. The process of claim 1, in which thestabilizing agent is added to the bleaching bath in an amount betweenabout 6 % and about 15 % calculated for 35% hydrogen peroxide presenttherein.
 3. bleaching the cellulose-containing textile fiber materialwith said stabilizing agent containing bath without substantiallyreducing the degree of polymerization of the cellulose present in thefiber material.
 3. BLEACHING THE CELLULOSE-CONTAINING TEXTILE FIBERMATERIAL WITH SAID STABILIZING AGENT CONTAINING BATH WITHOUTSUBSTANTIALLY REDUCING THE DEGREE OF POLYMERIZATION OF THE CELLULOSEPRESENT IN THE FIBER MATERIAL.
 4. The process of claim 1 furthercomprising adding to the silicate-free hydrogen peroxide-containingbleaching bath, in addition to the stabilizing agent, a polyaminocarboxylic acid.
 5. The process of claim 1, in which the alkylene groupof the stabilizing amino alkylene phosphonic acid has 1 to 6 carbonatoms.
 6. The process of claim 1, in which the alkane group of thestabilizing hydroxy alkane phosphonic acid has 1 to 3 carbon atoms. 7.The process of claim 1, in which the stabilIzing hydroxy compound is acompound selected from the group consisting of gluconic acid, citricacid, erythritol, pentaerythritol, sorbitol, and triethanolamine.
 8. Theprocess of claim 4, in which the polyamino carboxylic acid is an acidselected from the group consisting of ethylene diamino tetra-aceticacid, nitrilo tri-acetic acid, and diethylene triamino penta-aceticacid.
 9. The process of claim 1, in which bleaching is effected at atemperature between about 110* C. and about 145* C.
 10. The process ofclaim 1, in which the cellulose-containing textile fiber material is afiber material containing cellulose fibers in mixture with syntheticfibers.
 11. The process of claim 1, in which the cellulose-containingtextile fiber material is a fiber material containing cellulose fibersin mixture with polyester fibers.